Why Hashed OTP Tokens Are Better Than Storing Them in a Database

One-time passwords (OTPs) are crucial for securing applications, but how you store these tokens can significantly impact security and performance. Let’s discuss why using hashed OTP tokens is preferable to saving them in plaintext in a database, including the implications for database transactions, security breaches, and costs.

1. Database Transactions: The Cost of Storing OTPs

Imagine running a campaign where you store OTPs in a database. For each OTP check, several database transactions occur:

• Write Transaction: When generating an OTP, a write transaction is needed to store the OTP.
• Read Transaction: Each time a user attempts to verify their OTP, a read transaction retrieves the stored OTP.
• Update Transaction: If you implement any expiry logic, you might need to update the record once the OTP is used or expires.

This can quickly add up, especially during high-traffic events, leading to increased load on your database and potential performance bottlenecks.

2. Security Risks of Plaintext Storage

Storing OTPs as plaintext is a significant security risk. If an attacker gains access to your database, they can easily retrieve and misuse these OTPs. This compromises the entire authentication process, allowing unauthorized access to user accounts.

3. Cost Implications on AWS DB

Using hashed OTPs eliminates the need for database write operations altogether. After generating the hashed token, it can be returned directly in response to the front end, where it can be stored temporarily (e.g., in memory or local storage). This approach avoids any database interactions, significantly reducing costs associated with AWS databases.

By managing the hashed token entirely on the client side, you streamline OTP verification and improve performance during high-load scenarios without the overhead of database operations.

4. Implementation Demo with Laravel Advanced OTP

Using the Laravel Advanced OTP package, you can seamlessly implement hashed OTPs. Here’s a step-by-step demo:

Generate OTP and Send It via Email

// Generate OTP and send it via email
$otp = \LaravelAdvancedOTP::handle(LoginOTP::class, [
    'secret' => 'secret_key',  // Required to hash and verify OTP
    'email' => 'user_email@example.com',  // Email of the recipient
]);

// Get the hashed token for verification
$token = $otp->getHashedKey();

// Send OTP to user's email
$otp->send('user_email@example.com');

// Return the hashed token for later verification
return response()->json(['token' => $token]);

In this snippet, an OTP is generated and sent to the user's email. The hashed token is returned for verification.

Verify the OTP

$otp = request('otp');
$hashedToken = request('token');  // Token returned when sending OTP

$signature = [
    'secret' => 'secret_key',  // Same secret used during OTP generation
    'email' => 'user_email@example.com',
];

// Verify the OTP using the hashed token
$otpStatus = \LaravelAdvancedOTP::verify(LoginOTP::class, $otp, $signature, $hashedToken);

if ($otpStatus == OTPStatusEnum::NOT_VERIFIED) {
    // OTP is invalid
}

if ($otpStatus == OTPStatusEnum::VERIFIED) {
    // OTP is valid
}

if ($otpStatus == OTPStatusEnum::EXPIRED) {
    // OTP has expired
}

In this verification step, the user submits the OTP and the hashed token. The system checks the validity, ensuring a secure process without storing sensitive information.

Conclusion

Hashed OTP tokens are a superior choice for securing OTP verification. They minimize database transactions, enhance security, and reduce costs associated with data storage. By using the Laravel Advanced OTP package, you can easily implement this method in your Laravel applications, providing a robust and efficient solution for user authentication.

For further details, check out the Laravel Advanced OTP repository.